Comcast Mail Delaying & Failing Delivery
I need some help. My exchange server, which has been sitting behind the same block of Comcast IP Addresses for almost 5 years, are now not delivering messages to @comcast.net addresses. I get the dreaded Delivery Delayed followed by it eventually not delivering.
I have verified I am delivering to all other domains fine, nothing has changed internally and I am on no blacklists or blocklists.
Can someone please give me some help on fixing this? If the rDNS records for my IPs is not correct, it just started affecting us and I need it fixed or some other issue is causing it.
Error I am getting is 421 4.2.1 Unable to connect - Then it talks about failing to failover to alternate hosts, etc...
This just started happening a few days ago, till then, never had this issue at all.
Thank you in advance.